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United States Patent |
5,532,777
|
Zanen
|
July 2, 1996
|
Single lens apparatus for three-dimensional imaging having focus-related
convergence compensation
Abstract
The invention comprises an adapter having a set of four mirrors in two
pairs located in front of a camera lens. The outer two mirrors face
generally outward along the optical axis of the lens and the inner two
mirrors face generally inward into the lens. The centers of the outer two
mirrors are spaced apart by an appropriate interocular distance. The two
inside mirrors are together large enough to cover the complete viewing
area of the lens, each taking exactly half of the lens viewing area. The
two outside mirrors are bigger then the inside pair and large enough to
cover the viewing area of the inside pair to avoid viewing area reduction.
The convergence of the two outer mirrors is adjustable by swiveling them
simultaneously and equally about their centerlines with a ganging
mechanism. The two center mirrors may be fixed, or could be adjustable by
being swiveled so that one side of each remains in tight contact with the
other along the optical axis of the camera lens, and each makes a
45.degree. or lesser angle to the optical axis. The whole assembly is to
be housed in a dust and light proof housing that mounts onto the lens.
Inventors:
|
Zanen; Pieter O. (107 Cayuga Heights Rd., Ithaca, NY 14850)
|
Appl. No.:
|
470130 |
Filed:
|
June 6, 1995 |
Current U.S. Class: |
396/326; 348/49; 352/60; 356/3.15 |
Intern'l Class: |
G03B 035/08 |
Field of Search: |
356/3.14
354/114
348/49
352/60
|
References Cited
U.S. Patent Documents
3254933 | Jan., 1963 | Latulippe.
| |
3891313 | Jun., 1975 | Murphy | 353/8.
|
4178090 | Dec., 1979 | Marks et al.
| |
4436369 | Mar., 1984 | Bukowski.
| |
4523226 | Jun., 1985 | Lipton et al.
| |
4525045 | Jun., 1985 | Fazekus.
| |
4568970 | Feb., 1986 | Rockstead.
| |
4583117 | Apr., 1986 | Lipton et al.
| |
4687310 | Aug., 1987 | Cuvillier.
| |
5349403 | Sep., 1994 | Lo | 354/114.
|
Primary Examiner: Hellner; Mark
Attorney, Agent or Firm: Barnard, Brown & Michaels
Claims
What is claimed is:
1. A lens attachment for creation of three-dimensional images using a
single lens, for use with lenses having a field of view symmetrical about
an optical axis and a focusing means for focusing the lens to a selected
distance, comprising:
a) a right and a left inner mirror, both inner mirrors being located in
front of the lens facing inwardly along the optical axis of the lens
toward the lens, covering substantially all of the field of view of the
lens, the inner mirrors being connected together at one edge at the
optical axis of the lens, such that the two inner mirrors form an acute
angle symmetrical about the optical axis of the lens;
b) a right and a left outer mirror, both being larger than the inner
mirrors and located outward of the inner mirrors, facing outward toward
the subject, such that the substantially all of the field of view of the
inner mirrors is covered by the outer mirrors, the outer mirrors being
pivotable about a vertical axis;
c) ganging means for simultaneously pivoting the outer mirrors about their
vertical axes in opposite senses, having a control input for actuating the
ganging means, such that a movement of the control input causes the right
and left outer mirrors to pivot equally, oppositely and simultaneously,
such that a movement of the control input in one direction causes the
fields of view of the outer mirrors to converge, and a movement of the
control input in the opposite direction causes the fields of view of the
outer mirrors to diverge; and
d) adapter means for moving the control input of the ganging means in
response to actuation of the focusing means of the lens, connected to the
control input of the ganging means and the focusing means of the lens,
such that when the lens is focused at a selected distance, the field of
view of the outer mirrors converges at the selected distance.
2. The lens attachment of claim 1, in which each of the inner mirrors is
mounted at an angle of 45.degree. to the optical axis of the lens.
3. The lens attachment of claim 1 further comprising tandem means for
adjusting the angle of the inner mirrors to the optical axis of the lens,
such that both inner mirrors maintain the same angle to the optical axis
of the lens as the angle is adjusted.
4. The lens attachment of claim 3 in which the tandem means for adjusting
the angle of the inner mirrors comprises:
a) a center block located at the intersection of the optical axis of the
lens and the centerline of the outer mirrors, having a first bore oriented
along the optical axis of the lens, and a second bore along the centerline
of the mirrors;
b) a center pivot at the point where the edges of the two inner mirrors are
connected together, the connection between the two mirrors being movable;
c) a slide located on the centerline of the mirrors, passing through the
second bore in the center block and centered on the optical axis of the
lens, having two ends and a length sufficient that the ends of the slide
extend at least past the inner mirrors on the centerline of the mirrors;
d) two sliding pivots, each having a bore through which the slide is
slidably inserted, and a pivot upon which one of the inner mirrors is
pivotably mounted at its centerline;
such that when the center pivot is moved along the optical axis toward the
center block, the sliding pivots to which the inner mirrors are attached
slide outward on the slide and the inner mirrors pivot thereon, flattening
the angle between the inner mirrors and the optical axis and maintaining
each inner mirror at the same angle to the optical axis of the lens.
5. The attachment of claim 4, in which the first bore of the center block
is threaded; and the attachment further comprises a threaded adjustment
rod having matching threads, passing through the first bore of the center
block and being attached to the center pivot, such that the center pivot
is moved along the optical axis of the lens as the threaded adjustment rod
is turned within the threaded first bore.
6. The lens attachment of claim 3 in which the tandem means for adjusting
the angle of the inner mirrors comprises:
a) a center pivot at the point where the edges of the two inner mirrors are
connected together, the connection between the two mirrors being movable;
b) a first ganging rod, having a first end flexibly attached to an inner
mirror near the edge of the mirror most remote from the center pivot and a
second end flexibly attached to the outer mirror located on the same side
of the optical axis of the lens;
c) a second ganging rod, having a first end flexibly attached to the other
inner mirror near the edge of the mirror most remote from the center pivot
at the same point of attachment as the first end of the first ganging rod
is attached to its inner mirror, and a second end flexibly attached to the
outer mirror located on the same side of the optical axis of the lens at a
point on the outer mirror which is the same point at which the second end
of the first ganging rod is attached to its outer mirror;
such that when the outer mirrors are moved upon their pivots, the first and
second ganging rods cause the inner mirrors to move equally, oppositely,
and simultaneously.
7. The attachment of claim 6, in which the point of attachment of the
second end of the first and second ganging rods to the outer mirrors is
near the center of the outer mirrors.
8. The attachment of claim 6, in which the point of attachment of the
second end of the first and second ganging rods to the outer mirrors is
near the pivot point of the outer mirrors.
9. The attachment of claim 1, in which the ganging means comprises:
a) a center pinion gear located on the centerline of the mirrors;
b) a mirror pinion gear located at the vertical axis of one of the outer
mirrors, such that turning the mirror pinion gear pivots the outer mirror
along its vertical axes;
c) a rack operatively connecting the center pinion gear to the mirror
pinion gear, such that turning the center pinion gear moves the rack
linearly, causing the mirror pinion gear to rotate and pivot the outer
mirror; and
d) tying means for causing the other outer mirror to move equally and
oppositely to the outer mirror having the mirror pinion gear.
10. The attachment of claim 9 in which the tying means for causing the
outer mirror to pivot comprises a ganging rod connected to one end of the
right outer mirror and to the opposite end of the left outer mirror.
11. The attachment of claim 9 in which the tying means for causing the
outer mirror to pivot comprises a second mirror pinion gear and a second
rack connecting the center pinion gear to the second mirror pinion gear,
such that turning the center pinion gear moves the second rack linearly,
causing the second mirror pinion gear to rotate and pivot the outer mirror
equally and oppositely to the pivoting of the other outer mirror.
12. The attachment of claim 9 in which the control input of the ganging
means comprises a control rack connected to the center pinion gear, such
that linear movement of the control rack causes the center pinion gear to
rotate.
13. The attachment of claim 1 in which the adapter means for moving the
control input of the ganging means in response to actuation of the
focusing ring of the lens comprises:
a) an adapter sleeve surrounding at least part of the focusing ring of the
lens, connected thereto for rotation therewith, having a spiral groove
impressed therein;
b) a pin located on the control input;
c) the pin being held in the spiral groove of the adapter sleeve, such that
rotation of the adapter sleeve causes the pin to be moved linearly and
proportionally to the rotation of the adapter sleeve.
14. The attachment of claim 13, in which the spiral groove is configured
such that the linear motion of the pin causes the ganging means to pivot
the outer mirrors such that the field of view of the outer mirrors
converges at the selected distance of focus of the lens as the distance of
focus is changed by focusing the lens.
15. The attachment of claim 1, in which the ganging means for pivoting the
outer mirrors comprises a pair of rods having outer ends attached to the
outer mirrors, spaced a distance from the vertical axis about which the
outer mirrors are pivoted, and inner ends connected to each other and to
an actuating rod located parallel to the optical axis of the lens.
16. The attachment of claim 1, in which the vertical axis about which the
outer mirrors pivot is located at the inner end of the outer mirrors, the
outer mirrors further comprise an offset rod having a first end connected
to the outer mirror at the vertical axis thereof, and extending rearwardly
from the pivot, and having a second end, and the ganging means for
pivoting the outer mirrors comprises a pair of rods having outer ends
attached to the second end of the offset rods, and inner ends connected to
each other and to an actuating rod located parallel to the optical axis of
the lens.
17. The attachment of claim 1, in which the adapter means comprises an
electrical actuator having an electrical input for an electrical signal
representative of the focus of the lens and a mechanical output connected
to the control input of the ganging means, having a movement responsive to
the electrical signal on the electrical input, such that the electrical
signal representative of the focus of the lens adjusts the convergence of
the mirrors appropriately to the point of focus of the lens.
18. The attachment of claim 17, in which the electrical actuator is a
solenoid.
19. The attachment of claim 17, in which the electrical actuator is a
stepper switch.
20. The attachment of claim 17, in which the electrical actuator is a
servo.
21. The attachment of claim 1 in which the lens is a variable focal length
lens, and the adapter means is moved in response to the change in focal
length of the lens.
Description
FIELD OF THE INVENTION
The invention pertains to the field of stereographic or "3D" photography.
More particularly, the invention pertains to lens attachments to permit
acquisition of simultaneous left and right views using a single camera and
lens, which link the convergence angle of the views with the focus or
focal length of the lens.
BACKGROUND OF THE INVENTION
Stereographic photography is the method of producing images which are
apparently three dimensional by recording separate left- and right-eye
images. The viewer reconstructs the 3-D image by viewing the two separate
2-D images simultaneously. Stereographic photography has been known since
at least the late 19th century, when stereo viewers were a popular parlor
accessory.
Such stereo views have historically been created with two lenses on a
single camera, spaced apart by approximately the inter-ocular distance of
a human head. The Stereo Realist.TM. series of 35 mm still cameras,
popular in the 1950's, are an example of this kind of imaging. Left and
right views were recorded simultaneously through two lens/shutter sets on
alternate frames of the 35 mm film. The later Nimslo.TM. system used four
lenses for essentially the same approach.
Stereo movies appeared in the 1950's. The images were typically created
either using two synchronized cameras, or a two-lens system on a single
camera. Similarly, the various Stereo TV systems have typically used two
cameras (see Lipton, et al, U.S. Pat. No. 4,583,117) or a single camera
with two lenses (Lipton, et al, U.S. Pat. No. 4,523,226).
All of the multiple-camera systems have severe drawbacks, in the added
complexity and cost of duplicating the complete camera system and the
synchronization of the two separate images (this is especially a problem
in film (non-video) applications). In addition, the use of two separate
lenses (whether on one camera or two) introduces problems of synchronizing
focus and view.
The need for solving this latter problem is real, but not addressed by
prior art devices. Simply mounting two cameras side-by-side will allow the
taking of the left- and right-eye images, and the cameras can be focused
on whatever the subject is (although follow-focus of moving objects is
problematic). However, there is more to stereoscopic vision than simply
having two eyes. A simple experiment will demonstrate the problem. If one
holds up a finger at arms length, and brings it closer and closer to the
face, it becomes apparent that your eyes do more than merely focus on the
finger as it approaches. You also aim each eye independently, becoming
more and more "cross-eyed" as the finger nears the face. Without this
adaptation, most 3-D films tended to induce discomfort as the apparent
image distance to the view changed, since the camera views would not shift
as one's instinct might expect.
In addition, fixed convergence or partially or manually adjustable
convergence systems do not address the problem that the overlap of the
views must change as the focus and/or focal length of the lens changes.
The overlap of the two images should be maximized, especially in systems
which digitize the two images and use the information to form a three
dimensional picture of the surroundings.
There have been a number of devices aimed at simplifying the stereographic
process by allowing use of a single camera to take the two images. Most of
these use a number of mirrors or prisms, either in front of the camera
lens or between a secondary lens and a pair of primary lenses.
One method, useful only with motion pictures, is to sequentially record the
two images on alternate frames of the film or video. For film, a
synchronized spinning mirror is used to select the view to be recorded in
synch with the film gate or video scan. For such a device, see Latulippe,
U.S. Pat. No. 3,254,933. In video, the system electronically selects
alternate frames from two sources. This method has several disadvantages,
requiring complicated synchronized glasses for viewing and being
applicable only to movie or video applications.
The other alternative is to record both images simultaneously on each
frame, side-by-side or one above the other. This method is applicable to
any form of photography, still or moving, silver image or video. Viewing
is simplified, since both images are always present, and the adapter to
use a single lens does not need to be synchronized to the film transport
or video scan.
Simple prism- or mirror-based stereographic adapters have been available
for still cameras for some time. They fit in front of the camera lens in
the same manner as an accessory close-up or telephoto adapter. They have
no means for adjusting the adapter for convergence or focus as the
subject-lens distance changes.
Marks, et al, U.S. Pat. No. 4,178,090, creates vertically displaced left
and right images on a single frame using an attachment in front of a
single lens. One image is straight-through, with the second being taken
through a pair of prisms. An adjustable block in front of the lens is
solid glass on the top and reflective on the bottom. Convergence is
adjusted as the lens is focused by mechanically coupling a rotation
control for the adjustable block and a worm gear rotating the lens focus
control. This adjustment is insufficient for true automatic convergence
control with focus, as only one of the two views changes angle as the
block is rotated.
Bukowski (Optimax III, Inc.) U.S. Pat. No. 4,436,369, shows a mirror-based
adapter using two primary lenses with ganged focusing mechanisms. Two
pairs of fixed mirrors direct the left and right images to the top and
bottom of the film frame. The optical axes of the lenses are parallel and
fixed, which means that the convergence or aim point of the two lenses is
not changed as the lenses are focused.
Fazekas (Panavision, Inc.) U.S. Pat. No. 4,525,045, also has two primary
lenses and two pairs of fixed mirrors/prisms. A "horizon adjustment" is
provided to allow the cameraman to move one lens to compensate for the
vertical displacement of the two lenses, but the optical axes of the
lenses are fixed and parallel.
Rockstead, U.S. Pat. No. 4,568,970, uses an adapter which fits in front of
the lens of a television camera. Pairs of mirrors (FIG. 1) or prisms (FIG.
2) are used to create the pair of images on the video frame, and a similar
device in front of the viewer's eyes reconstructs the two images back into
a 3-D single image. A knob allows the operator to manually adjust the
convergence of optical axes of the mirrors/prisms to create the two
side-by-side images.
SUMMARY OF THE INVENTION
The invention comprises an adapter having a set of four mirrors in two
pairs located in front of a camera lens. The centers of the four mirrors
are all aligned on a common centerline, with the outer two mirrors facing
generally outward along the optical axis of the lens and the inner two
mirrors facing generally inward into the lens. The centers of the outer
two mirrors are spaced apart by an appropriate interocular distance. The
two inside mirrors are together large enough to cover the complete viewing
area of the lens, each taking half of the lens viewing area. The two
outside mirrors are bigger than the inside pair and large enough to cover
the viewing area of the inside pair to avoid viewing area reduction.
The convergence of the two outer mirrors is adjustable by swiveling them
simultaneously and equally about their centerlines with a ganging
mechanism. The two center mirrors may be fixed, or could be adjustable by
being swiveled so that one side of each remains in tight contact with the
other along the optical axis of the camera lens, and each makes a
45.degree. or lesser angle to the optical axis.
The actuating mechanism for the outer mirrors is connected to a ring that
fits tight around the focusing ring of the lens, so a change in focus
automatically leads to readjustment of the convergence of the images. The
whole assembly is to be housed in a dust and light proof housing that
mounts onto the lens.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows a view of the preferred embodiment of the mechanism of the
invention with automatic focus/convergence adjustment.
FIG. 2 shows an alternate embodiment with angle adjustment for the inner
mirrors and an alternate method of tying the two outer mirrors together.
FIG. 3 shows another alternate embodiment using rods in place of gears and
racks to move the outer mirrors, with the outer mirrors pivoted about a
vertical axis at their inner ends rather than their centers.
FIG. 4 is a schematic diagram of another alternate embodiment using rods to
move the outer mirrors.
FIG. 5 is a schematic diagram of another alternate embodiment using rods to
move the outer mirrors, similar to the embodiment of FIG. 4.
FIG. 6 is a schematic diagram of another alternate embodiment using rods to
move the outer mirrors, similar to the embodiment of FIG. 4, but with the
inner mirrors also adjusted.
FIG. 7 is a schematic diagram of another alternate embodiment using rods to
move the outer mirrors, similar to the embodiment of FIG. 6, but with the
inner mirrors adjusted at a different point, more appropriate to
convergence adjustment with focal length zoom.
FIG. 8 shows another embodiment, in which servos replace the pin-and-slot
mechanism of FIGS. 1 and 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a view of the invention, shown from the bottom of the camera
(1). The adapter of the invention is preferably housed in a water- and
dust-tight enclosure (19), which is conventional and details of which are
not shown. The adapter mounts upon camera (1) along the optical axis (10)
of the lens (4) by any appropriate means, such as the bar (3) and tripod
screw (2). No details are shown of the camera (1), since the adapter of
the invention is not specific to any particular kind of camera, still,
movie or video. The various parts of the adapter of the invention are
mounted upon or supported by and within the housing (19) by conventional
means which are not shown, for clarity in showing and describing the novel
points of the invention.
The invention uses four mirrors to create the required two images: two
inner mirrors (16) and two outer mirrors (12). The outer mirrors (12) are
spaced apart an appropriate distance, preferably an approximation of the
average human inter-ocular distance. For specialized applications, such as
surveillance or the like, the spacing can be increased within the
teachings of the invention. The two images from the outer mirrors (12) are
reflected to the inner mirrors (16) and into the lens (4) as a single
split side-by-side image.
In the preferred embodiment of the invention shown in FIG. 1, the inner
mirrors (16) are fixed in position, and the outer mirrors (12) swivel on
pivots (13) at their center. Dot-dashed line (11) shows that the centers
of the four mirrors are coaxial along line (11), which is perpendicular to
the optical axis of the lens represented by dot-dashed line (10).
The two outer mirrors (12) are ganged together so that they rotate
together, but in opposite senses (i.e. one rotates clockwise when the
other is rotated counterclockwise), so that the effect is to vary the
convergence of the two mirrors simultaneously and equally. In the
arrangement of FIG. 1, the rotation of a central gear (17) is translated
into linear movement of a first (15) and second (18) rack, which ride on
opposite sides of the gear. The racks (15) and (18) then translate their
linear motion back into rotation of gears (14) on each mirror (12),
causing the mirrors (12) to rotate on their pivots (13).
As can be seen, the first rack (15) crosses over the mirror centerline
(11), to ride on the same side of its gear (14) as does the lower rack
(18) on its gear (14). This is necessary to insure that the two mirrors
(12) rotate in opposite senses. FIG. 2 shows another method of ganging the
mirrors (12) to rotate oppositely, in which there is only one rack (18) to
move one mirror (12) directly, and the other mirror is moved by cross-rod
(25) which connects opposite ends of each mirror. Another possible
arrangement would be to use a crossed ("figure-8") belt or chain to
connect the gears on the two mirrors.
The central gear (17) is rotated by the linear in-and-out movement of rack
(8). Attached to the end of the rack (8) is a pin (9), which slides along
a slot (7) in mounting bracket (3). Thus, movement of the pin toward or
away from the camera (1) causes the rack (8) to rotate the central gear
(17), which in turn, through racks (15) and (18) pivots mirrors (12)
equally in opposite directions.
The camera lens (4) has a sleeve (6) attached around its focusing ring, so
that rotation of the sleeve (6) causes the lens (4) to be focused. This
ring (6) could be slip-fit to the lens, or would preferably have one or
more set-screws to firmly fix it to the focusing ring.
The sleeve (6) has a slot (5) machined into it, and the pin (9) on rack (8)
fits into this slot. Through this arrangement, rotation of the focusing
mechanism of the lens causes the sleeve (6) to rotate. The slot (5) forces
the pin (9) to move the rack (8) in or out, which rotates the outer
mirrors (12) accordingly as noted above.
In its simplest form, if all things were perfect, the slot (5) need only be
a simple spiral groove along the sleeve (6). Unfortunately, most lenses do
not focus entirely in a linear fashion. That is, a given degree of
rotation of the focusing ring does not always correspond to a similar
change in lens to subject distance. The adjustment of the mirror
convergence may or may not follow the nonlinearity of the lens focusing in
a linear fashion. Thus, it can be seen that slot (5) will need to be made
non-linear as well. In FIGS. 1 and 2 it is shown in two different
non-linear forms. The actual form of the slot (5) will need to be
determined for each combination of lens and mirrors.
Thus, the attachment of the invention permits split-screen left/right
images to be produced using a conventional single-lens camera, in which
the convergence of the left and right images is automatically controlled
by the focusing of the camera lens. In summary, as the lens (4) is focused
by rotating the focusing ring, the sleeve (6) around the ring also
rotates. A pin (9) riding in an appropriately shaped slot (5) in the
sleeve (6) moves a rack (8) in or out. The motion of the rack (8) rotates
a central gear (17), which, in turn, adjusts the convergence of the outer
mirrors (12) through at least one rack (15). The other mirror (12) is
moved simultaneously and equally in the opposite sense through a ganging
mechanism. This ganging mechanism can be a second rack (18), or a simple
tie (25, FIG. 2) between the mirrors.
FIG. 2 shows how the inner mirrors (16) can be adjusted, if desired, to
allow for corrections of the field of view or the like. Mirrors (16) are
hinged together at the point where they meet to a pivot (23) which is
attached to the end of a threaded rod (21) which runs along the optical
axis (10) of the lens (4). The rod has a knob (20) on its opposite end,
protruding out of the case (19) to allow it to be adjusted by the user.
The threaded rod (21) is threaded through a block (24) through which a
slide (26) passes perpendicularly, along the centerline of the mirrors
(11). The two inner mirrors (16) are mounted at their centerpoints on
pivots (22) which can slide freely along the slide (26). Thus, when the
knob (20) is turned, the threaded rod (21) turns within the block (24),
causing the center pivot (23) at its end to be drawn closer to or further
away from the block (24). As the center pivot (23) moves closer to the
block, the pivots (22) slide along the slide (26), flattening the angle
between mirrors (16). Similarly, if center pivot (23) is moved further
away from the block (24), the pivots (22) slide inwardly, drawing mirrors
(16) to a more acute angle.
FIG. 3 shows another, simpler, alternative embodiment of the invention. The
activating mechanism on the lens remains the same as the preceding
embodiments, through rack (8) and central disk (35). Two activating rods
(32) and (33) connect diametrically opposed points on central disk (35) to
offset rods (30) attached to the outer mirror (12) vertical pivots (13),
which are located at the inner end of the mirrors. Pivot connections (31)
ensure free movement of the rods, as the mechanism is moved. As the lens
ring (4) is focused toward a subject closer to the lens, the pin (9) is
moved outwards by slot (5), pushing rack (8) away. This rotates the pinion
gear (17), which in turn rotates the central disk (35) counterclockwise.
As central disk (35) is rotated counterclockwise, activating rods (32) and
(33) move outwards, pushing on offset rods (30) and pivoting the outer
mirrors (12) inward. This causes the field of view of the outer mirrors
(12) to converge.
FIGS. 4 through 7 are schematic representations of additional embodiments
of the invention. In each case, push-pull rod (43) is moved toward or away
from the lens (not shown) as the lens is focused or zoomed, whether by a
slot and pin arrangement as shown in the earlier figures, by servos as
shown in FIG. 8, or by some other means. In each of these figures, the
outer mirrors (12) are mounted by vertical pivots (45) on their inner ends
to a frame (44). The inner mirrors (16) may also be mounted to the same
frame (44), fixedly as shown in FIGS. 4 and 5, or by pivot (62) as shown
in FIGS. 6 and 7.
In FIG. 4, the outer mirrors (12) are simply activated by extending rod
(43) past the frame (44) to a pivot connection (41) at a point between the
two outer mirrors (12). Activating rods (42) connect this pivot to the
mirrors (12) through additional pivot connections (41) outwardly on the
mirrors. As the push-pull rod (43) is drawn backward toward the lens (as
shown by the dotted arrow), fields of view of the outer mirrors (12) are
converged.
FIG. 5 is similar, using the same arrangement of activating rods (42) and
pivot connections (41), but located behind the frame (44) and mirrors (12)
and (16). The outer mirrors (12) are activated by offset rods (50),
similar to those used in FIG. 3. In this case, pushing the push-pull rod
(43) away from the lens causes the convergence of the fields of view of
the outer mirrors (12).
FIG. 6 uses the same arrangement as FIG. 5 to move the outer mirrors (12).
The inner mirrors (16) are also activated in this arrangement, by running
inner mirror rods (60) from the outer ends of the inner mirrors (16) to a
point close to the vertical pivot axis (45) of the outer mirrors (12).
Moving this point of attachment, as shown in FIG. 7, will allow the
designer to adjust the relative movement of the inner (16) and outer (12)
mirrors. In FIG. 7, the attachment point of the inner mirror rods (60) is
moved to approximately the center of the outer mirrors (12), which causes
the inner mirrors (16) to move more relative to the outer mirrors than the
arrangement in FIG. 6. The pivot point (62) of the inner mirrors (16) is
moved to a point which is in line with the pivots (45) of the outer
mirrors (12). As a result of these changes from the arrangement of FIG. 6
is that the inner (16) and outer (12) mirrors remain parallel and move the
same amount as the angle between the mirrors and the optical axis of the
lens is changed. The FIG. 7 arrangement is useful in applications where
the push-pull rod is moved in response to changes in focal length (zoom)
than focus.
Some autofocus or electrically focused lenses do not have focusing rings
which rotate as the lens is focused, or perhaps the focus ring is on the
inside of the lens barrel or otherwise not easily accessible for a
mechanical arrangement such as the slot-and-pin mechanism of FIGS. 1 to 3.
The adapter of the invention can still be used with such camera systems.
As shown in FIG. 8, an electrical actuator (85) such as a stepper motor,
servo, or solenoid can be used to drive activation rods (83) to rotate the
outer mirrors (12) through offset rods (30). Of course, this particular
arrangement of rods is shown for example, and the other arrangements shown
in FIGS. 1 to 7, or some other variant, could also be used. If desired,
another electrical actuator (84) could be added to separately adjust inner
mirrors (16), through a mechanism such as inner activating rods (82) and
inner offset rods (81). The two electrical activators can be operated by
electrical circuitry of any kind known to the art, such as microprocessors
or discrete driver circuits, driven by the same circuitry which focuses
and, optionally, zooms the lens (4). Alternatively, an activating signal
could be derived from an electrical position sensor physically mounted to
the lens.
Accordingly, it is to be understood that the embodiments of the invention
herein described are merely illustrative of the application of the
principles of the invention. Reference herein to details of the
illustrated embodiments are not intended to limit the scope of the claims,
which themselves recite those features regarded as essential to the
invention.
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